U.S. authorities issued subpoenas to Goldman Sachs for documents related to the bank's dealings with troubled Malaysia state wealth fund 1MDB, The Wall Street Journal reported, citing a person familiar with the matter.

Separately, Singapore's central bank said on Saturday it is examining the extent of Goldman's local unit's involvement in bond deals for 1MDB.

"MAS supervisory examination into the extent of Goldman Sachs (Singapore) Pte's involvement in the 1MDB bond deals is still ongoing," a MAS spokeswoman said in an email statement to Reuters.

The MAS has been questioning banks and financial institutions since last year as part of investigations into possible money laundering in the city state linked to 1MDB.

A Goldman Sachs' spokesman in Hong Kong declined to comment on the Singapore inquiry. 1MDB has said in the past it is not a party to the civil suit, does not have any assets in the United States of America, nor has it benefited from the various transactions described in the civil suit.

This month the DOJ launched what it said was the largest-ever asset seizure case - worth more than $1 billion - under its Kleptocracy Asset Recovery Initiative, alleging that a total of $3.5 billion was misappropriated from 1MDB, a wealth fund established in 2009 by Malaysian Prime Minister Najib Razak, who also chaired the fund's advisory board.

In 2012 and 2013, Goldman arranged and underwrote three bond sales that raised $6.5 billion for the fund - services which the bank was paid almost $600 million, according to multiple reports.

The DOJ alleged the misappropriated funds - much of which were the proceeds of the Goldman-managed bond sales - were laundered through shell companies with bank accounts in Singapore, Switzerland, Luxembourg and the U.S., then distributed to people who are known to be close to Najib. These people then spent the cash on assets including high-end real estate and artworks, according to the DOJ.

Goh Seng Chong | Bloomberg | Getty Images

Signage for 1Malaysia Development Bhd. (1MDB) is displayed at the site of the Tun Razak Exchange (TRX) project in Kuala Lumpur, Malaysia.

Goldman, which faces a separate civil lawsuit over the bond sales, has said previously that it had no visibility on what happened to the funds raised after the bond sales were conducted. The bank did not immediately respond to an out-of-business-hours request for fresh comment.

The Malaysian Prime Minister has repeatedly and vociferously denied any wrongdoing in relation to 1MDB.

Last week Najib's office said that the Malaysian Government would "fully cooperate with any lawful investigation of Malaysian companies or citizens in accordance with international protocols." "As the Prime Minister has always maintained, if any wrongdoing is proven, the law will be enforced without exception," Najib's press secretary said.

A spokesman for the Prime Minister did not immediately respond to an out-of-business hours request for fresh comment.